Vacuum milling and deaerating system



Oct. 20, 1959 D. J. BROWN ETAL 2,909,332

VACUUM MILLING AND DEAERATING SYSTEM I Filed Nov. 5, 1954 2 Sheets-Sheet1 LAME/V05 B. SCHAUER DONALD J. BROWN 1 N VENTOR ATTORNEY Oct. 20, 1959D. J. BROWN ETAL VACUUM MILLING AND DEAERATING SYSTEM Filed Nov. 5, 19542 Sheets-Sheet 2 GLEN/V H MOREHOUSE LAWRENCE B. SOHAUER DONALD J. BROWNINVENTOR ATTORNEY by mesne assignments, 'to Morehouse Industries, -Inc.,Los Angeles, Calif., a corporation of California Application November'5, 1954, Serial No. 467,098

8 Claims. (Cl. 241-46) This invention relates to a system for thepreparation of products which require a grinding, comminuting or mixingin their preparation, wherein the entrainment of gases is prevented andalso wherein previously entrained gases are removed.

In the preparation of aqueous ,products solids areground in the presenceof a liquid. For example, a fruit nectar may be prepared by subjecting afruit to a grinding action so that all of the materials intermixed withthe liquid are reduced to very fine size, the product being therebygiven a creamy consistency. Oleaginous products are also prepared bysubjecting the oils or greases and the materials to be combinedtherewith to a grinding action in a mill whether the products beingprepared are aqueous or oleaginous in their nature, there is ordinarilyan entrainment of gas, for example, air, during and as the result of thegrinding process. The entrainment of gas in the aqueous :products isharmful, and in the preparation of oleaginous products by milling, theentrainment of air may result in a large increase in the bulk of theproduct. It is an object of the present invention to provide -a systemand method for the preparation of products which require -a grindingaction. Herein the term grinding is used in its broader sense as meaningthe reduction in size of solids or semisolids entering into the productand the thorough intermixing of the same with the aqueous or oleaginousvehicle of the product.

It is an object of the invention to provide a system including a grinderwhich receives the product to be prepared by grinding action, a meansfor applying a suction to the outlet of the chamber of grinder which ismade airtight so that air cannot enter thereinto, and flow restrictingor controlling means connected to the inlet of the grinding chamber sothat the feeding of the product to be milled is accomplished in such amanner that a partial vacuum is maintained in the grinding chamber. Inthis system entrained gases are removed from the constituent parts ofthe product and entrainment of gases in the product is prevented.

It is an object of the invention to provide a system including asubstantially airtight grinder having an inlet and an outlet, with agear pump connected to the outlet nited States Patent so as tocontinuously withdraw the'milled product from the grinder chamber, and agear pump connected to the inlet of the chamber through which theproduct to be milled passes to the chamber, there being means forcontrolling operation of the gear pump so as to cause the gear pump toadmit the product to be milled to the chamber of the mill at a ratewhich is less than the rate at which the suction gear pump is capable ofwithdrawing fluids from the outlet of the chamber, the result being thata partial vacuum is maintained in the system between the inlet gear pumpand the suction gear pump, to maintain in the chamber of the mill acondition of partial vacuum in which the milling operation takes place.

Further objects and advantages of the invention may be brought out inthe following part of the specification wherein small details of apreferred form of the inven- 2,909,332 Patented Oct. 20, 1-959 ice tionhave been described for the purpose of making a complete disclosure,without the intention of limiting the scope of the invention set forthin the appended-claims.

Referring to the drawings which are for illustrative purposes only:

Fig. 1 is a schematic view showing a preferred form of our system;

Fig. 2 is a fragmentary schematic view showing the control valveadjusted to another position;

Fig. 3 is a schematic view of a form of the invention forming a completegrease making system; and

Fig. 4 is a fragmentary schematic view showingano'ther position of oneof the valves of the system shown in-Fig. 3.

As shown in Fig. 1, we provide a grinder 10 having a lower part 11and-an upper part 12 defining alg'rinding chamber :13 having an inletspace 14 and an outlet space 15, the upper part llsupports-therein astationary annular grinding element 16 and the lower *part :11supports abearing 17 which carries a vertical shaft 18 which projects upwardlyinto the grinding chamber 13 and supports thcrein a rotating grindingelement 19 to cooperate with the stationary grinding element 16. Thebearing 17 is supported within avertical tubular wall 20, forming aportion of the lower part 11, by cylindrical sleeve elements 21 and 22,there being a sealing means 23 to seal around the shaft -18 in a mannerto'pievent entry of air from the exterior into the grinding chai'nb'er13.

The rotating grinding element 19 is supported upon a circular plate 24having a cylindrical hub 25 which projects downwardly around the upperportion of the shaft 18. The sealing means 23 consists in part 'of aring 26 which is fixed on the hub 25 so as to rotate therewith, and anon-rotating ring 27 which is supported below the ring 26 by acylindrical insert 28 arranged within the sleeve member 22 above thebear-ing .17. The lower p'art of the outlet space 15 of the chamber 13is closed 'by 'a ring 29 secured by screws 30 and having in theperiphery thereof a groove to receive a sealing ring 32. The shaft 18 isdriven by a motor 33 at high velocity.

- The product to be milled is disposed in a hopper 3'4 and the lowerIpart of this hopper 34 is connected through a valve '35 and a flowcontrolling or restricting means 36 with the inlet 37 of thegrindingchamber lS. From the inlet space 13 of the chamber '14 the productpasses through the narrow space 38 between the grinding elements 16 and1-9 which are ordinarily made from stone especially selected for thispurpose. The milled product passes into the outlet space 15 of thechamber 13 "and from this space .passes through an outlet '40 in thering 29 through a duct member 41 to a valve port =42-of a multiplepassage valve 43 which is schematically shown as having a valve body 44with passages 45 'and 46 therein. The valve 43 is of a type disclosed incopending application, Serial No. 357,204, filed May 25, 1953, nowPatent No. 2,741,326. This valve device has "a port 47 which isconnected through a duct member 48 with the inlet port 49 of a gear pump50 such as disclosed in said copending application. The valve device 43has a port 51 which is connected through a duct member 52 with theoutlet port 53 of the pump 50, and the valve device also has a dischargeor outlet port 54 which is connected to a duct member 55 which carriesthe fihished, deaerated product to selected receivers, such as drums,storage vats, etc. The outlet duct 41 which leads from the grinding ormilling chamber :13 is also connected to an auxiliary reservoir '56,this connection being made through avalve "57. V p I The flowrestricting, ine'tering or controlling means 66, in the preferred 'formof the invention, consists of a gear pump having meshed gears 58, therotation of which is controlled by an electric motor which acts througha a 3 variable speed gear 60 to drive a chain 61 which runs over asprocket 62 fixed on one of the shafts of the pump 36. The gear 60 hasmeans such as a handle 63 whereby it may be controlled so as to vary therate of flow of the product through the pump 36 to the inlet 37 of themill 10.

When the valve 43 is adjusted as shown in Fig. 1, the operation of thepump 50 will create a suction in the duct members 48 and 41 tending towithdraw fluid or the milled product through the outlet opening 40 ofthe mill 10, at a rate which is determined by the size and speed ofoperation of the pump 50. The pump 36, being connected to the motor 59,is capable of being adjusted so that the rate of fiow therethrough ofthe product to be milled is less than the rate of flow of which the pump50 is instantly capable. This results in the creation of a partialvacuum in the system between the pump 36 and the pump 50'. It may besaid that the suction pump 50 creates a partial vacuum in the millingchamber 12 and the pump 36 prevents entry of air from the outsidethrough the inlet 37 into the system, but at a controlled rate feeds theproduct to be milled to the inlet 37 of the mill 10.

When the valve body 44 is rotated into the position in which it is shownin Fig. 2, the passage 46 will directly connect the valve ports 51 and47 so that there will be no flow of the finished product through theduct member 55, but the outlet port 53 of the pump 50 will be directlyconnected to its inlet port 49 for recirculation of the finished productduring the time the discharge duct 55 is being connected to anotherreceiver. At this time the valve 57 may be opened so that some of themilled product may pass into the auxiliary reservoir 56. When the valvebody 44 is readjusted into the position in which it is shown in Fig. 1,the quantity of the product contained in the receptacle 56 may bereturned into the system. At this time the valve 57 will be adjusted sothat it will restrict the rate of flow of the product toward the valveport 42 so that the action of the suction pump 50 will create a partialvacuum in the system between the pump 36 and the pump 50.

In Fig. 3, I show the sealed mill as part of a complete grease makingsystem. Therein a mixing device 60 is provided for combining theingredients prior to the milling and deaerating operations. It providesmeans for heating and mixing the components which enter into compoundedgreases such as metallic greases, metallic soap greases and lithium soapgreases. A shell 61 is provided having a steam jacket 62 adapted toreceive steam as a heating medium. A vertical shaft 63 extends down intothe shell 61 and carries thereon mixing and scraper blades 64. The upperend of the shaft 63 is connected to a power source shown as a motor 65.An outlet pipe 66, having a valve 67 therein extends to the inlet of agear pump 68. The outlet of the gear pump 68 is connected by a ductmember-'69 with a three-way valve 70. The upper outlet of the three-wayvalve 70 is connected to a return pipe 7'1 leading to the upper portionof the mixing device 60. The lower outlet of the three-way valve 70 isconnected by a duct member 72 with the inlet of the sealed mill 10.

A suction pump 50 of herringbone gear type is provided having a motor 73to drive the same. Means are provided whereby the outlet 74 of the mill10 may be connected to the inlet of the suction pump 50 or to returnpiping leading to the mixing device, for recirculation of the milledproduct. From the outlet 74 of the mill 10 a duct 75 is extended to theport 76 of valve means 77 having a body 78 with passages 79 and 80therein. When the body 78 is in the position in which it is shown inFig. 3, the valve passage 79 connects the port 76 with a duct means 81leading to the inlet 82 of the suction pump 50, the duct means 81including a chamber 83 having therein a screen 84 through which themilled grease passes. At this time the. valv p s g connects a ductmember 85 with an outlet duct 86. The duct member 85 is connected to theoutlet 87 of the suction pump 50, and 'the duct 86 is connected to theinlet port of a three-way valve 88 having a valve passage 89 arranged tobe connected with a delivery pipe 90 as shown in full lines in Fig. 3.

When the body 78 of the valve means 77 is rotated in clockwise directionthrough an angle of approximately 90, the valve passage 79, as shown inFig. 4, will conmeet the duct means 81 with the duct member 85, therebyconnecting the outlet 87 of the suction pump 50 with its inlet 82. Atthe same time, as shown in Fig. 4, the valve passage 80 will connect theduct 75, which leads from the outlet 74 of the mill 10, with a ductmember 91 which, as shown in Fig. 3, extends to the upper portion of themixing device 60. Rotation of the body of the valve 88 incounterclockwise direction through an angle of substantially 90 willbring the valve passage 89 into a position 89' wherein it will connectthe duct member 86 with a duct member 92 which connects with the ductmember 91.

The pump 68 is operated or controlled by a power source shown as anelectric motor 93 which is connected to a variable speed drive 94 havingcontrol means including a lever 95. The transmission 94 is connected tothe pump 86 through a chain and sprocket means 96.

The system disclosed in Fig. 3 may be operated as follows. The shell 61is charged with the simple grease, soap and other substances which areto enter into the finished, milled greased product. The body 97 of thevalve 70 is adjusted so that its valve passage 98 will connect the duct69 with the return duct 71. The power source 65 is operated so as torotate the blades 64 within the shell 61, and steam is delivered to thejacket 62 to provide heat for the mixing operation. The motor 93 is thenoperated to drive the pump 68 so that the partly mixed ingredients willbe drawn from the bottom of the shell 61, and through the gears of thepump 68 and then returned to the shell 61 by the return duct 71. Thisprocedure is carried on during the heating and mixing of theingredients. A feature of the arrangement described is that theingredients are acted upon by the gears of the pump 68 which serves tobreak up small lumps of the different ingredients so that a better andfaster mixing thereof may be eifected in the mixing device 60.

After the preliminary mixing and heating described in the foregoing,with the valve body 78 in the position in which it is shown in Fig. 3,the mill 10 and the pump 50 are set into operation. The body 97 of thevalve 70 is then rotated in counterclockwise direction through an angleof substantially 90 so that the passage 98 thereof, as shown at 98 willconnect the duct 69 leading from the outlet of the pump 68 to the ductmember 72 which is connected to the inlet of the mill 10. The handle ofthe variable speed transmission 94 will be then adjusted rightwardlyfrom the position in which it is shown in full lines to reduce the speedof the gears of the gear pump 68, so that the gear pump 68 will thenserve as a valve means for controlling the rate of flow of the greasemixture through the duct member 72 to the inlet of the mill 10. Thesuction exerted by the pump 50 will, during the operation of this partof the process, draw the grease mixture through the mill at such ratewith relation to the operation of the pump 68 that a state of partialvacuum will be established in the zone in which the milling operation isbeing performed and the desired deaerating effect will be attained. Atthis time the threeway valve 88 may be actuated so as to connect thedelivery duct 86 with the duct member 92, so that the milled anddeaerated grease will be delivered through a portion of the duct member91, whereupon the grease may be subjected to further action in themixing device 60 or may be again circulated through the system. Also,rotation of the bgdy 78 of the valve 77 into the position thereof shownin Fig. 4 will 'connect' the outlet duct 75 of the mill directly withthe return duct member 91, thereby making-it possible to recirculate thegrease product seriate'ly through the mixer and the mill any selectednumber of times before subjecting the grease product to the final .stepof milling under vacuum and deaerating, which may be accomplished byoperation of 'themotor 73 to drive the suction pump 50', adjustment ofthe valves 77 and 88 into the positions in which-they are shown in Fig.3 and adjustment of the flow rate of the pump 68 to a value less thanthe flow rate of the pump 50.

The milling of the product underpartial vacuum effects the bursting ofthe air bubbles which are so small that they will not separate from thegrease, so that the small bubbles are agglomerated into large "bubblesor masses of air. Also, as the grease passes through the screen 84, airbubbles existing therein are broken so as to release therefrom therelatively small bodies of air which combine to form larger air massesas explained in US. Letters Patent No. 2,660,259, granted to Glenn H.Morehouse November 23, 1953. The bodies of grease and masses of air areconsecutively drawn from the piping 81 and discharged through the piping85 and 86. Upon reaching the open atmosphere the bodies of grease willdrop into a suitable container provided therefor and the masses of airwill pass into the atmosphere.

We claim:

1. In a milling and deaerating system: a mill having a closed millingchamber having an inlet and an outlet, and having a rotor in saidchamber supported by a shaft and a seal around said shaft; a gear pumphaving its inlet connected to the outlet of said chamber for applyingsuction to the outlet of said chamber; an auxiliary reservoir betweensaid chamber and said pump; multiple passage valve means disposedbetween said chamber and said pump arranged when in one of its positionsto connect the inlet of said pump to the outlet of said chamber and toconnect the outlet of said pump to outlet piping for the finishedproduct, and when in another position to connect the outlet of said pumpdirectly to its inlet; valve means operable to connect the outlet ofsaid mill to said reservoir; a gear pump connected to the inlet of saidchamber through which the product to be milled passes to said chamber;and means for controlling the operation of said last named gear pump sothat it will act as a valve to restrict the flow of the product to bemilled into said chamber to a rate less than the rate at which saidfirst named gear pump is endeavoring to draw the product from the outletof the chamber, thereby creating a vacuum in said system between saidpumps and effecting removal of entrained gases from the product.

2. In a milling and deaerating system: a mill having a ,closed millingchamber having an inlet and an outlet, and having a rotor in saidchamber supported by a shaft and a seal around said shaft; a gear pumpfor applying suction to the outlet of said chamber; multiple passagevalve means connected to the outlet of said chamber and to the inlet andthe outlet of said pump arranged when in one of its positions to connectthe inlet of said pump to the outlet of said chamber and to connect theoutlet of said pump to outlet piping for the finished product, and whenin another position to connect the outlet of said pump directly to itsinlet; a gear pump connected to the inlet of said chamber through whichthe product to be milled passes to said chamber; and means forcontrolling the operation of said last named gear pump so that it willact as a valve to restrict the flow of the product to be milled intosaid chamber to a rate less than the rate at which said first named gearpump is endeavoring to draw the product from the outlet of the chamber,creating a vacuum in said system between said pumps and eflectingremoval of entrained gases from the product.

3. In a milling and deaerating system: a mill having a closed millingchamber having an inlet and an outlet, and having a rotor in saidchamber supported by a shaft and a seal around said shaft; a suctionpump having its inlet connected to receive the milled material from theoutlet "of said chamber so that said pump will act to draw the milledproduct through said chamber outlet; metering means connected to theinlet of said chamber through which the product to be milled passes tosaid chamber; and means for controllingthe operation of said meteringmeans so that it will act 'as a valve to restrict the flow of theproduct to be milled into said chamber to a rate less than the rate atwhich said pump 'is endeavoring to draw the product from the outlet ofthe chamber, therebycrea'ting a vacuum in said system between saidmetering means and said suction pump and effecting removal of entrainedgases from the product.

'4. An apparatus as recited 'in claim 3 wherein said suction Lpumpcomprises a gear pump and said metering means comprises a feed gearpump.

5. In a milling a'nddeaerating system: a-mill having a closed millingchamber having an inlet and an outlet, and having a rotor in saidchamber supported by a shaft and a seal around said shaft; a gear pumphaving its inlet connected to the outlet of said chamber for applyingsuction to the outlet of said chamber; an auxiliary reservoir betweensaid chamber and said pump; multiple passage valve means disposedbetween said chamber and said pump arranged when in one of its positionsto connect the inlet of said pump to the outlet of said chamber and toconnect the outlet of said pump to outlet piping for the finishedproduct, and when in another position to connect the outlet of said pumpdirectly to its inlet; valve means operable to connect the outlet ofsaid mill to said reservoir; and means for restricting the flow of theproduct to be milled into said chamber to a rate less than the rate atwhich said gear pump is endeavoring to draw the product from the outletof the chamber, creating a vacuum in said system between said pump andsaid flow restriction means and effecting removal of entrained gasesfrom the product.

6. In a milling and deaerating system: a mill having a closed millingchamber having an inlet and an outlet, and having a rotor in saidchamber supported by a shaft and a seal around said shaft; a gear pumphaving its inlet connected to the outlet of said chamber for applyingsuction to the outlet of said chamber; multiple passage valve meansconnected to the outlet of said chamber and to the inlet and the outletof said pump arranged when in one of its positions to connect the inletof said pump to the outlet of said chamber and to connect the outlet ofsaid pump to outlet piping for the finished product, and when in anotherposition to connect the outlet of said pump directly to its inlet; andmeans for restricting the flow of the product to be milled into saidchamber to a rate less than the rate at which said gear pump isendeavoring to draw the product from the outlet of the chamber, creatinga vacuum in said system between said pump and said flow restrictionmeans and efiecting removal of entrained gases from the product.

7. In a milling and deaerating system: a mill having a closed millingchamber having an inlet and an outlet; a gear pump having its inletconnected to the outlet of said chamber for applying suction to theoutlet of said chamber; an auxiliary reservoir between said chamber andsaid pump; multiple passage valve means disposed between said chamberand said pump arranged when in one of its positions to connect the inletof said pump to the outlet of said chamber and to connect the outlet ofsaid pump to outlet piping for the finished product, and when in anotherposition to connect the outlet of said pump directly to its inlet; valvemeans operableto connect the outlet of said mill to said reservoir; andmeans for restricting the flow of the product to be milled into saidchamber to a rate less than the rate at which said first named gear pumpis endeavoring to draw the product from the outlet of the chamber,thereby creating a vacuum in said chamber and efiecting removal ofentrained gases from the product.

8. In a milling and deaerating system: a mill having a closed millingchamber having an inlet and an outlet; pump means having its inletconnected to the outlet of said chamber for applying a continuoussuction to the outlet of said chamber; an auxiliary reservoir betweensaid chamber and said pump; multiple passage valve means disposedbetween said chamber and said pump arranged when in one of its positionsto connect the inlet of said pump to the outlet of said chamber and toconnect the outlet of said pump to outlet piping for the finishedproduct; means for connecting the outlet of said mill to said reservoir;and means for restricting the flow of the product to be milled into saidchamber so that the system between said pump and said restricting meanswill be held under vacuum and removal of entrained gases from theproduct will be eifected.

References Citedin the file of this patent UNITED STATES PATENTS

